An electrochromic device (ECD) typically comprises a conducting substrate coated with a working electrode material, a conducting substrate coated with a counter electrode material, and an electrolyte placed between the electrodes and facing the electrode active material coatings, each of these elements being in the form of a film.
The conducting substrate can be made of a non conducting sheet coated by a conducting film. The non conducting substrate can be made for instance of glass. It can also be made of a non conducting polymer e.g. polyethylene terephthalate PET) for flexible ECD's. The conducting film may be a film of a transparent conducting oxide (TCO). The TCO may be ITO, or a doped zinc oxide (AZO, GZO, SZO), or a fluorine doped oxide (FTO) (WO2008/064878). The conductive film may also be a film of a conducting polymer, such as for instance a PDOT.
The electrolyte can be in liquid, gel or solid (polymer) form.
The active material of the working electrode may be an organic or an inorganic oxide, or polymers obtained from monomers derived from alkylene dioxythiophenes (PDOT). A number of active materials, in particular polymers, are disclosed in WO2008/064878.
The active material of the counter electrode may be Prussian Blue (PB) LiFePO4, NiOx, a conductive polymer (such as polyaniline, polythiophene or polypyrrole), or HxIrO2. See for instance WO2009-098415.
A. J. Widjaja, et al. [Solar Energy Materials & Solar Cells, 92 (2008) 97-100] teach a method for preparing an ECD where at least one element is prepared by a R2R method. However, Widjaja teaches the use of R2R in a general way, the only material which is illustrated being WO3, and concludes that it might not be obvious for the skilled person to use the R2R method for any material which is part of an ECD.
The known methods allow production of ECD's having good performance. However, they generally do not allow continuous manufacturing of ECD's of large dimensions.
The aim of embodiments of the present disclosure is to provide a method for producing large dimension mechanically flexible transparent ECD's possibly by a continuous method.